1. Technical Field
This disclosure relates to a liquid ejection head and an image forming apparatus, and in particular to a liquid ejection head ejecting liquid drops and an image forming apparatus employing the liquid ejection head.
2. Discussion of the Background Art
An image forming apparatus, such a printer, a facsimile, a copier, a complex machine configured by combining these devices, etc., sometimes employs a liquid ejection device that includes a printing head having a liquid ejection head for ejecting and adhering liquid drops onto a medium, such as a paper, a string, a texture, a towel, a leather, a metal, a plastic, a glass, woods, ceramics, etc., while conveying the printing sheet to form an image.
The image formation includes not only a meaningful image, such as a character, a figure, etc., but also a meaningless image, such as a pattern, etc. The liquid is not limited to printing liquid or ink, but includes every type of liquid as far it is capable of executing image formation. The liquid ejection device generally ejects liquid from a liquid ejection head.
As one example of such a liquid ejection head employed in an image forming includes a heater in a nozzle plate to eject liquid drops from the nozzle while deforming the nozzle plate using a difference in heat expansion has been known as discussed in Japanese Patent Application Laid Open No. 2001-105590.
Various types of a liquid ejection head that deforms a nozzle plate including a flexible film by heat are described in the Japanese Patent Application Laid Open Nos. 2002-359981 and 2004-160650 as well as the Japanese Patent Registration No. 2827544.
There is a type that changes a fluidity resistance by connecting a vibration plate and a piezoelectric element to a bottom of the fluidity resistance flow path communicated with one end of the pressurizing chamber as described in the Japanese Patent Application Laid Open No. 2001-063047.
Since a liquid ejection head generally ejects liquid drops from a nozzle by pressurizing a liquid chamber or a flow path, pressure preferably does not leak from the liquid chamber when the pressure in the liquid chamber is to be efficiently increased and is applied to the liquid drops to be ejected. Thus, a liquid resistance section is arranged in the flow path that supplies liquid to the liquid chamber. In this point of view, the Japanese Patent Application Laid Open No. 2001-063047 employs a device capable of increasing the fluidity resistance when liquid drops are ejected.
However, these prior arts are still insufficient.